Notification Bubble's Colour

Dear lazy web, I've been pondering for a while how to correctly implement notifications bubbles coloring. Yesterday I've threw together a simple patch that reads the colour from gtkrc (the same way the upstream default theme does). It solves a problem with text not being readable on bubbles when using dark themes. The problem is, that the bubbles apparently have same colours like windows, whereas I'd like them to have same colours like tooltips. Does anyone knows whatever to target in gtkrc theme in order to achieve that goal?

Current look:



After patch: